1. Field of the Invention
The present invention relates to a power amplifier for amplifying high frequency signals, etc. used, e.g., in mobile communications.
2. Background Art
Japanese Laid-Open Patent Publication No. 2001-148616 discloses a power amplifier that includes a chip having a plurality of field effect transistors (FETs). Resistive elements are formed in the chip and across the closed loops formed on the chip, in order to prevent loop oscillation on the chip. These resistive elements are resistances formed from an epitaxial layer. (Such resistances are hereinafter referred to as epi resistances.)
In order to prevent loop oscillation by absorbing its oscillation power, it is desirable that the resistive elements described above have a resistance value of approximately a few to a few tens of ohms. In the case of the power amplifier disclosed in the above publication, however, it has been found difficult to control the resistance values of these resistive elements, since they are epi resistances.